#include <bits/stdc++.h>
using namespace std;
struct cww{cww(){ios::sync_with_stdio(false);cin.tie(0);}}star;
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define vv(type, c, m, n, i) vector<vector<type>> c(m, vector<type>(n, i))
#define mat(type, c, m, n) vector<vector<type>> c(m, vector<type>(n));for(auto& r:c)for(auto& i:r)cin>>i;
#define rep(i,a,n) for(int i=(a), i##_len=(n); i<i##_len; ++i)
#define rrep(i,a,n) for(int i=(a), i##_len=(n); i>i##_len; --i)
#define each(x,y) for(auto &(x):(y))
#define var(type, ...)type __VA_ARGS__;Scan(__VA_ARGS__);
template<typename T> void Scan(T& t) { cin >> t; }
template<typename First, typename...Rest>void Scan(First& first, Rest&...rest) { cin >> first; Scan(rest...); }
#define vec(type, c, n) vector<type> c(n);for(auto& i:c) cin>>i;
#define len(x) ((int)(x).size())
#define mp make_pair
#define eb emplace_back
#define em emplace
#define pb pop_back
#define fi first
#define se second
#define get(a, i) get<i>(a)
#define bit_count __builtin_popcount
#define mt make_tuple
typedef long long ll;
typedef long double ld;
typedef vector<int> vi;
typedef vector<double> vd;
typedef vector<long long> vll;
typedef vector<string> vs;
typedef vector<bool> vb;
typedef pair<int, int> pii;
#define mini min_element
#define maxi max_element
#define sum accumulate
#define chmax(a,b) if(a<b)a=b
#define chmin(a,b) if(a>b)a=b
template <class T> inline void print(T t){cout << t << "\n";}
template <class H, class... T> inline void print(H h, T... t){cout << h << " ";print(t...);}
vs S;
vector<pii> vp;
int len_vp = 0;
int ans = 10, n;
void f(int a) {
	if (a == len_vp) {
		vector<pii> v(n);
		rep(i, 0, n) {
			v[i] = mp(count(all(S[i]), 'o'), i);
		}
		sort(rall(v));
		int num = 1, last = v[0].fi;
		rep(i, 1, n) {
			if (v[i].fi != last) {
				++num;
			}
			if (v[i].se == 0)
				break;
		}
		chmin(ans, num);
		return;
	}
	S[vp[a].fi][vp[a].se] = 'o';
	S[vp[a].se][vp[a].fi] = 'x';
	f(a + 1);
	S[vp[a].fi][vp[a].se] = 'x';
	S[vp[a].se][vp[a].fi] = 'o';
	f(a + 1);
}
int main() {
	cin >> n;
	rep(i, 0, n) {string s; cin >> s; S.eb(s);}
	rep(i, 0, n) {
		rep(j, 1, n) {
			if (S[i][j] == '-')
				vp.eb(mp(i, j));
		}
	}
	len_vp = len(vp);
	f(0);
	print(ans);
	return 0;
}